The principal of Concord's Highlands Elementary has sent a letter to parents over an effort to split the district.

Ryan Sheehy is worried his school's population will be cut in half if Walnut Creek's Northgate neighborhood succeeds in splitting off from the Mt. Diablo School District. "It would take away about 53 percent of our student population and about 15-20 members of our state," Sheehy said.

Mt. Diablo currently serves 32,000 students. Northgate parents have started their own drive in the effort to secede from Mt. Diablo and form their own district with three elementary schools, a middle school, and one high school. Highlands would remain in MDUSD, but Sheehy says as many as 300 of his students, 53-percent of the current school population, could be pulled into the new Northgate district. The new Northgate district would have just 4200 students, pulled from the affluent neighborhoods of Walnut Creek.

The Contra Costa County School Board will take up the proposed split later this month. Final approval would have to come from the California Board of Education.